This invention relates to a thermally conductive material that is utilized to transfer heat from a heat-generating electronic device to a cold sink that absorbs and dissipates the transferred heat.
Electronic devices, such as those containing semiconductors, typically generate a significant amount of heat during operation. In order to cool the semiconductors, cold sinks are typically affixed in some manner to the device. In operation, heat generated during use is transferred from the semiconductor to the cold sink where the heat is harmlessly dissipated. In order to maximize the heat transfer from the semiconductor to the cold sink, a thermally conductive thermal interface material is utilized. The thermal interface material ideally provides an intimate contact between the cold sink and the semiconductor to facilitate the heat transfer. Commonly, either a paste-like thermally conductive material, such as silicone grease, or a sheet-like thermally conductive material, such as silicone rubber is utilized as the thermal interface material.
Both the current paste-like and sheet-like thermally conductive materials have drawbacks that present obstacles during their use. For example, while some paste-like materials provide low thermal resistance, they must be applied in a liquid or semi-solid state and thus require manufacturing controls in order to optimize their application. In addition to enhanced controls during application, the handling of the paste-like materials can be difficult. Difficulties in utilizing existing materials include controls upon reapplication for pastes, migration of grease to unwanted areas, and reworkability for phase change materials or thermoset pastes. Traditional thermal interface films address the handling and application problems of pastes, however they typically have a higher thermal resistance as compared to pastes. Thus, it would be advantageous to provide a thermal interface material that is easy to handle and apply, yet also provides a low thermal resistance.
A composition for use as a thermal interface material in a heat-generating, semiconductor-containing device is provided. The composition comprises a blend of fluoroelastomer components that are copolymers of hexafluoropropylene and vinylidene and consists of greater than 40% fluorine along the backbone. The blend contains at least one component with a Mooney viscosity of 50 poise or less and at least one component with a Mooney viscosity of greater than 50 poise.
Another aspect of the present invention provides an electronic device containing a heat-generating component, a cold sink and a thermal interface material according to the above description.